1. Field of the Invention
The present invention relates generally to the field of wireless communications, and in particular, to a receiving device and method in a base station (BS), for locating a mobile station (MS).
2. Description of the Related Art
The FCC (Federal Communication Committee) of the U.S. provides that an MS locating service should be implemented for emergency 911 (E911) public safety services. The FCC requires that wireless carriers be able to locate an E-911 caller with an accuracy of 125 meters in 67% of the cases by October, 2001. Therefore, the CDMA (Code Division Multiple Access) standard (TIA/EIA/IS-95) as well as the IMT-2000 (International Mobile Telecommunication-2000) system makes efforts to provide the MS locating service with use of a reverse link function called "PUF (Power Up Function)". The PUF is an MS locating scheme in which an MS in an emergency situation transmits probes with gradually increased power to a plurality of adjacent BSs on a reverse channel to inform them of its position so that each of the BSs can calculate the distance between the BS and the MS by estimating the time taken for the signal to reach the BS. The PUF is provided in IS-95B. However, the PUF of IS-95B may decrease system performance since an MS increases its transmit power on its own decision. That is, the increased transmit power of the specific MS creates interference with other MSs. Then, a BS continuously performs power control to reduce the transmit power of the specific MS, thereby increasing system load. Therefore, there exists the need for a continuous positioning service which does not degrade system performance by increasing interference.